How can use draw tool in sculpture mode? (red line)
The red line is from the &quot;Stabilize Stroke&quot; brush settings. It adds a delay to your stroke indicated by the red line. Drag further and the draw tool will work at the end of the line.
You can turn it off in the brush settings. Open the sidebar in Sculpt mode (N) or look at the tool panel on the right side of the screen: Brush Settings → Stroke → Stabilize Stroke